A Novel Two-Step Hybrid Quantum Watermarking Technique

The paper presents a novel hybrid quantum water-marking method designed to enhance the security and robustness of digital media protection. The proposed scheme integrates a two-step encryption process, achieving high security while pre-serving quality. Key features include classical LSB substitution, quantum chaos matrix, and an improved quantum representation, offering superior resistance to attacks. By combining spatial and transform domain encryption, the method overcomes vulner-abilities in singular value decomposition, enhancing robustness and peak signal-to-noise ratio (PSNR). Compared to the latest developments-such as sinusoidal-tent map, multi-scale pattern-based quantum text watermarking (MPQTW), maximum pixel difference, tri-way pixel, and NEQR with Quantum Majority Finder (QMF)-the proposed approach shows an average PSNR improvement of approximately 20 % and a significant reduction in Bit Error Rate (BER) by 15.41 %. Additionally, the method demonstrates strong resistance to various attack types with a correlation two-dimensional (Corr 2D) value near 1, such as 0.994 against salt and pepper noise attacks. These results highlight a significant advancement in quantum watermarking technology, balancing improved perceptual quality, security, and robustness.